Boats may be lowered into water using a boat lift assembly. Typically such a boat lift assembly comprises one or more winches. At least one cable wraps around each winch and connects the winches to a platform. The boat can be positioned over the platform. Rotation of the winches moves the cables, and the cables in turn move the platform and carry the boat up and down.
Preferably the cable should wind around the winch without crossing or tangling. This is accomplished by cable tension. Most known manufacturers of boat lift assemblies use what are known as scrubbers to help maintain cable tension. Scrubbers are a piece of rubber or plastic mounted on a plate and pressed against the cable. However, these parts wear out quickly and require lots of maintenance and repair, with attendant costs. U.S. Pat. No. 5,988,941 to Sargent et al discloses a similar concept where a boat lift cable lock apparatus provides a mounting bracket for defining a tapered cable channel. The tapered channel engages the cable to produces a friction lock helping to maintain tension in the cable. However, friction is a high variable phenomena, subject to the vagaries of materials, age, temperature and other environmental considerations. U.S. Pat. No. 6,935,807 to Becker discloses a weight attached to the cable which maintains tension on the cable to keep the cable from damaging a boatlift or a boat. However, adding a weight and/or springs drives up the costs and complexity of a boat lift assembly, and in some designs use of a weight is not practical. It would be desirable to provide a boat lift assembly which reduces the likelihood of uncontrolled movement of the cable and which increases the operating life of the cable.